1. Field of the Invention
The present invention relates to an optical transceiver for carrying out a single-wire two-way communication by using an optical fiber. In detail, the present invention particularly relates to an optical transceiver, wherein an optical fiber is fixed by inserting into a via hole formed in a circuit board, and an optical integration chip on which a light emitting element and a light receiving element are formed on the same chip is mounted oppositely to the via hole, and thereby a single-wire two-way communication is carried out in a simple structure.
2. Description of Related Art
An apparatus for carrying out an optical communication using an optical fiber is provided with an optical transceiver for outputting to the optical fiber by converting an electric signal into an optical signal through a light emitting element, and converting an optical signal from the optical fiber into an electric signal through a light receiving element for outputting.
The conventional optical transceiver is typically designed such that each of the light emitting element and the light receiving element is mounted on an individual metallic can package or a silicon sub-mount, and the respective element is individually adjusted and fixed so as to obtain the excellent optical coupling with the optical fiber.
Also in a system where a single optical fiber is not only used as an optical fiber through which a transmitting light emitted from the light emitting element is passed, but also used as an optical fiber through which an externally receiving light is passed, namely, a so-called single-wire two-way communication system, the system requires a lens for collecting lights, a beam splitter for separating optical paths, and the like in addition to the light emitting element and the light receiving element (for example, refer to a patent document 1: Japanese Laid Open Patent Application JP-A-Heisei, 9-325245).
FIG. 21 is a plan view showing a configuration example of the conventional optical transceiver. A transmitting light emitted from a light emitting element 100 is collected by a lens 101, transmitted through a beam splitter 102, and inputted to a core section of an optical fiber 103, and then propagated. Also, a receiving light transmitted through the optical fiber 103 from external is reflected by the beam splitter 102, and the optical path is separated from that of the transmitting light. Then, the receiving light is inputted to a light receiving element 104, and converted into an electric signal.
However, in the conventional optical transceiver, individual adjusting and fixing works for each of the light emitting element and the light receiving element were required relative to the optical fiber. Thus, the number of assembling steps was increased to thereby lead to a large increase in cost. Similarly, a large number of members for adjusting and fixing were required to thereby increase the number of components, which led to the large increase in the cost. Also, the conventional optical transceiver required a substrate made of silicon that had a V-groove to support the optical fiber, components using expensive materials such as a lens made of glass and the like, and complex processes to make those components. Hence, the cost of the components and the processing cost were increased to thereby lead to the large increase in the total cost.
Also, in order to carry out the single-wire two-way communication, an optical isolator was required to reduce the influence of crosstalk of lights on the transmitting side and the receiving side. This led to increase the number of the components and increase the cost of the components. Also, the beam splitter that was the optical component for separating the optical path was very expensive, so that this also led to the increase in the total cost of the optical transceiver.
Moreover, when the light emitting element and the light receiving element were mounted, very high precisions were required to the mounting positions of both the elements. Thus, in order to minimize their errors, the number of the assembling steps, especially, the number of the steps necessary for the adjustment was increased to thereby lead to the large increase in the cost.
The present invention is accomplished in order to solve the above mentioned problems. Accordingly, there has been a need to provide an optical transceiver that has a simple structure and a low cost, and attains a single-wire two-way communication.